2007-7459 2007-7459 S2007-74592018000300165 Venezuela 00 12 2018 00 12 2018 17 3 165 166 1 2013 30 2 2 283-7 2 PAHO WHO 1978 URSS 3 1972 4 Organización Panamericana de la Salud 2003 5 2007 21 2-3 2-3 177-85